Injection needle assembly

ABSTRACT

An injection needle assembly is presented having an injection needle where the distal pointed end is arranged to penetrate a membrane arranged at the proximal end of a medicament container; a tubular needle holder having a distal engagement means and proximal engagement means; a tubular cap having a proximal outer engagement means and proximal inner engagement means; a tubular needle cover comprising first engagement means arranged to cooperate with the proximal engagement means, and second engagement means arranged to cooperate with the proximal outer engagement means of the cap. The needle cover is arranged to be displaced from a first position wherein the second engagement means and the proximal outer engagement means prevents the needle cover and the needle holder to be axially displaced by a linear displacement, to a second position wherein the needle cover and the needle holder are distally displaced.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a division of U.S. patent application Ser.No. 13/847,541,filed Mar. 20, 2013, now U.S. Pat. No. 9,687,615, whichis a division of U.S. patent application Ser. No. 12/996,837, filed Jan.25, 2011, now U.S. Pat No. 8,708,970, which is a U.S. National PhaseApplication pursuant to 35 U.S.C. § 371 of International Application No.PCT/EP2009/056750 filed Jun. 2, 2009, which claims priority to U.S.Provisional Patent Application No. 61/060,191 filed Jun. 10, 2008 andSwedish Patent Application No. 0850110-8 filed Dec. 1, 2008. The entiredisclosure contents of these applications are herewith incorporated byreference into the present application.

FIELD OF THE INVENTION

The present invention relates to an injection needle for medicaldevices, and in particular sterile aspects of handling injectionneedles.

BACKGROUND

Many medicament delivery devices such as injectors are often developedfor self-administration, i.e. the user performs the injection. In orderto have a simple handling of the device it is often desirable to have itas pre-assembled as possible. Therefore often the injector is deliveredto the user with an injection needle pre-attached.

Another aspect of attachment of injection needles to medicamentcontainers is that the rear end of the injection needle often protrudesinto the interior of the container. This could be a drawback if themedicament reacts with the material of the needle when exposed for aperiod of time. In that respect it would be desirable to have the rearpart of the needle outside the container until the injection is to beperformed. On the other hand, this then requires that the rear end ofthe needle could be moved fairly easily into the container and also thatthe rear end of the needle is kept in a sterile environment until it ismoved into the container.

A few attempts have been done to solve this problem. Document U.S. Pat.No. 7,374,558 discloses an auto-injector having drive means forautomatic penetration and injection. At the front end of the injector asealed compartment is arranged, in which a sterile injection needle isarranged. When the injector is activated, the medicament container ispushed forward, whereby a membrane at the front end of the container ispenetrated by the rear end of the needle. After this the container andthe needle is advanced further, causing a penetration of the patient'sskin. After penetration the injection is performed automatically.

Documents U.S. Pat. Nos. 6,743,203 and 5,658,259 disclose similarauto-injectors having a needle positioned in a sterile compartment atthe front end of the injector, and where the rear of the needlepenetrates the medicament container upon activation in that thecontainer is pushed forward. Subsequent steps are penetration andinjection.

The above mentioned injectors require a lot of components and it isrelatively complicated to sterilize the injection needle and keep itsterile. Further, for multi-dose injectors requiring a needle changebefore each injection, the above mentioned solutions cannot be used.

Documents U.S. Pat. Nos. 2,828,742 and 3,916,893 disclose injectorshaving needles that are attached into a proximal neck portion of amedicament container such that a distal end of the injection needlepenetrates a membrane of the medicament container when a needle holderis distally displaced. One of the reasons for the design according to'742 and '893 is to keep a zone sterile between the medicament containerand the needle. In '742, the needle holder is distally displaced bymerely gripping a surrounding needle sheath that is of a flexiblematerial, such as rubber, thereby providing a risk of accidental needlesticks. Further, there is no locking/preventing means between the sheathand the cap/ferrule, which is a disadvantage if a user/patient removesthe sheath before the distal end of the injection needle penetrates themembrane, since the proximal end of the needle may be contaminatedor/and it may be difficult to position the sheath again in connectionwith the cap/ferrule. In '893, the needle holder is distally displacedby threading the sheath in one direction onto a cap/syringe body. Thereare no locking/preventing means between the needle holder and thecap/syringe body after the needle holder has been distally displaced.This is a disadvantage if the press fitting between the needle holderand the cap/syringe body is not enough to withstand the pressure exertedwhen expelling a liquid. Moreover, the removal of the sheath is noteither intuitive since the user/patient has to rotate the sheath back toremove it.

SUMMARY

The aim of the present invention is to provide an injection needleassembly comprising an injection needle that is kept sterile until use,which is kept out of contact with the medicament until use, and whichassembly is secure and easy to handle for a patient.

This aim is obtained by the injection needle assembly characterised bythe features of the independent patent claims. Preferable embodiments ofthe present invention are the subject of the dependent patent claims.

According to a main aspect of the invention, it is characterised by aneedle assembly having opposite distal and proximal ends, the assemblycomprises an injection needle having proximal and distal pointed ends,wherein the distal pointed end is arranged to penetrate a membranearranged at the proximal end of a medicament container; a tubular needleholder partially surrounding and fixedly connected to said injectionneedle, wherein said needle holder comprises on its outercircumferential surface distal engagement means and proximal engagementmeans; a tubular cap comprising a distal part having containerattachment means, a proximal part having proximal outer engagement meanson its outer circumferential surface, and a central passage havingproximal inner engagement means on its inner circumferential surfaceadapted for receiving the distal engagement means of the needle holder;a tubular needle cover comprising on its inner circumferential surface,first engagement means arranged to cooperate with the proximalengagement means of the needle holder, and second engagement meansarranged to cooperate with the proximal outer engagement means of thecap; wherein said needle cover is arranged to be displaced from a firstposition wherein the second engagement means and the proximal outerengagement means prevents the needle cover and the needle holder to beaxially displaced by a linear displacement, to a second position whereinthe needle cover and the needle holder are distally displaced, andwherein the proximal inner engagement means of the cap and the distalengagement means of the needle holder prevents the needle holder to beproximally displaced but allows the needle cover to be distallydisplaced.

According to another aspect of the invention, the second engagementmeans of the needle cover and the proximal outer engagement means of thecap; and the proximal inner engagement means of the cap and the distalengagement means of the needle holder are bayonet fittings.

According to a further aspect of the invention, the second engagementmeans of the needle cover and the proximal outer engagement means of thecap; and the proximal inner engagement means of the cap and the distalengagement means of the needle holder are threaded engagements.

According to yet an aspect of the invention, the distal part of the capis either attached to the proximal end of the container or attached toboth the proximal end of the container and to a housing part orcontainer holder of a delivery device by the container attachment means.

According to one aspect of the invention, the distal pointed end of theinjection needle is kept sterile by the protective cover.

There are a number of advantages with the present invention. Because theneedle assembly comprises three components, the cap, the needle holder,and the needle cover, wherein the cap and needle holder are displaceableand lockable in relation to each other, and wherein the cap and theneedle cover are displaceable and lockable in relation to each other;the injection needle could easily be moved from one position where it isnot in contact with medicament, but kept in a sterile environment, to aposition where it is in contact with the medicament, which preferably isjust before injection by the patient. Preferably the displacement of theholder is performed by the needle cover, which then has multiplefunctions, i.e. covering the needle from accidental needle sticks,keeping the needle sterile and displacing the needle in contact with themedicament such that an injection may be performed.

In order to ascertain the protection of the needle from the environmentthe needle cover is preferably press-fitted onto the cap, therebyensuring the sterility of the needle. The locking of the cap and theneedle cover in relation could preferably be performed by mechanicallocking means such as bayonet fittings or threads, which are lockingmeans that easily could be performed by handling of the needle cover.

Apart from the injection needle assembly the present invention naturallyalso comprises a medicament container arranged with the needle assembly.

These and other aspects of and advantages with the present inventionwill become apparent from the following detailed description and fromthe accompanying drawings.

BRIEF DESCRIPTION OF THE FIGURES

In the following detailed description of the invention, reference willbe made to the accompanying drawings, of which

FIG. 1 shows perspective view of a needle cover and of a protectivecover of the needle assembly of the present invention,

FIG. 2 shows a side view of a tubular cap and of a needle holder of FIG.1 without the needle cover,

FIG. 3 shows a side exploded view of FIG. 2,

FIG. 4 shows a perspective exploded view of FIG. 2,

FIG. 5 shows a perspective views of the needle cover and of the needleholder of FIG. 2 seen from their distal ends,

FIG. 6 shows a side view of a tubular cap and of a needle holder of avariant of the needle assembly,

FIG. 7 shows a perspective exploded view of FIG. 6,

FIG. 8 shows perspective views of the needle cover, of the needle holderand of the cap of FIG. 6 seen from their distal ends.

DETAILED DESCRIPTION

In the present application, when the term “distal part/end” is used,this refers to the part/end of the assembly, or the parts/ends of themembers thereof, which is/are located the furthest away from themedicament delivery site of the patient. Correspondingly, when the term“proximal part/end” is used, this refers to the part/end of theassembly, or the parts/ends of the members thereof, which, is/arelocated closest to the medicament delivery site of the patient.

The present invention is intended to be used in medicament injectiondevices, which could be of any type from simple manual injectors tomulti-function auto-injectors. However they do not form part of thepresent invention and are thus not shown in the drawings.

FIG. 1 shows a needle assembly 10 having opposite distal and proximalends according to the present invention. The assembly comprises aninjection needle 46 having proximal 48 and distal 50 pointed ends,wherein the distal pointed end is arranged to penetrate a membrane (notshown) arranged at the proximal end of a medicament container 24; atubular needle holder 40 partially surrounding and fixedly connected tosaid injection needle 46, wherein said needle holder comprises on itsouter circumferential surface distal engagement means 44; 70 andproximal engagement means 54; a tubular cap 26 comprising a distal part28 having container attachment means 30, a proximal part 32 havingproximal outer engagement means 60; 80 on its outer circumferentialsurface, and a central passage 34 having proximal inner engagement means36, 38; 72 on its inner circumferential surface adapted for receivingthe distal engagement means 44; 70 of the needle holder; a tubularneedle cover 12 comprising on its inner circumferential surface, firstengagement means 52 arranged to cooperate with the proximal engagementmeans 54 of the needle holder, and second engagement means 58; 78arranged to cooperate with the proximal outer engagement means 60; 80 ofthe cap; wherein said needle cover is arranged to be displaced from afirst position wherein the second engagement means 58; 78 and theproximal outer engagement means 60; 80 prevents the needle cover and theneedle holder to be axially displaced by a linear displacement, to asecond position wherein the needle cover and the needle holder aredistally displaced, and wherein the proximal inner engagement means 36,38; 72 of the cap and the distal engagement means 44; 70 of the needleholder prevents the needle holder to be proximally displaced but allowsthe needle cover to be distally displaced.

The needle cover 12 comprises a slightly conical proximal part 14, agenerally tubular distal part 16 and a central tubular part betweenthem, where the tubular distal part 16 has a somewhat larger diameterthan the central tubular part.

The cap 26 is tubularly shaped and thus has the central passage 34, FIG.4. The proximal inner engagement means on the central passage are atleast one longitudinally extending groove 36 ending in a generallytransversal groove 38, thereby forming a general T-shape, thus creatingone part of a bayonet fitting, FIG. 4.

The outer diameter of the distal end 42 of the needle holder generallycorresponds as the inner diameter of the passage 34, and is arrangedwith the distal engagement means as e.g. ledges 44, creating the otherpart of the bayonet fitting, intended to cooperate with the grooves 36,38; FIG. 4.

The tubular distal part 16 of the needle cover has a diameter thatsurround the container attachment means and the central part of theneedle cover has an inner diameter somewhat larger than the outerdiameter of the distal tubular part 28 of the cap 26, but such thatcentral part of the needle cover is press fitted onto the distal tubularpart 28 of the cap. The inner circumferential surface of the distaltubular part of the needle cover is provided with the first engagementmeans as e.g. three axially extending ledges, where each has a firstradial inwardly directed ledge 52, FIG. 5. These ledges 52 fit into theproximal engagement means of the needle holder e.g. cut-outs 54. Furtherthe inner circumferential surface of the distal tubular part of theneedle cover is arranged with the second engagement means 58 as e.g. aninwardly directed ledge, which is intended to fit into the proximalouter engagement means 60 of the cap as e.g. an -shaped groove having afirst transversal part, a first longitudinal part, a second transversalpart and a second longitudinal part.

The distal part 28 of the cap 26 is either attached to the proximal endof the container or attached to both the proximal end of the containerand to a housing part or container holder of a delivery device by thecontainer attachment means 30.

When the needle assembly is delivered to the user a portion of thedistal part of the needle holder is partially press fitted into the capand the radial distal front surface of the distal engagement means 44 ofthe needle holder abuts the radial proximal surface of the proximal part32 of the cap. Also, the inwardly directed ledge 58 of the needle cover12 is in engagement with the first transversal part of the bayonetfitting groove 60 and thereby an axial movement of both the needleholder and the needle cover is prevented.

For penetrating the membrane of the container with the distal pointedend 50 of the needle 46, the user twists the needle cover 12, wherebythe needle holder 40 also twists due to the connection between them viathe inwardly directed ledges 52 fitting into the cut-outs 54 of theneedle holder. This twisting also causes the inwardly directed ledge 58of the needle cover 12 to move out of the first transversal part of thebayonet fitting groove 60 on the outside of the cap 26, and the ledges44 of the needle holder 40 to fit into the longitudinal grooves 36 ofthe cap 26, thereby enabling both the needle cover 12 and the needleholder to be linearly pushed towards the distal end of the assembly.During the linear motion of the needle holder into the cap, the distalpointed end 50 of the injection needle 46 penetrates the membrane of themedicament container, thereby creating a passage from the interior ofthe container to the proximal pointed end 48 of the injection needle 46.

When the ledges 44 have reached the end of the longitudinal grooves 36the user twists further the needle cover 12, whereby the needle holder40 also twists due to the connection between them via the inwardlydirected ledges 52 fitting into the cut-outs 54 of the needle holder.The further twisting then causes the ledges 44 to fit into thetransversal groove 38, thereby causing a bayonet locking of the needleholder with the cap whereby the needle holder cannot be axiallydisplaced. The further twisting also causes and the inwardly directedledge 58 of the needle cover 12 to move through and out of the secondtransversal part of the bayonet fitting groove 60 on the outside of thecap 26. Now, the needle cover 12 may be pulled off the needle holder 40and the cap 26. The injection needle assembly is now ready forinjection.

FIGS. 6-8 show a variant of the embodiment of FIG. 1. Instead of bayonetfittings between the needle holder and the cap, and between the needlecover and the cap, the distal engagement of the needle holder 70 and theproximal inner engagement means 72 of the cap are threads 70, and theproximal outer engagement means 80 of the cap and the second engagementmeans 78 of the needle cover are also threads. Thus, when the needlecover is turned, the needle holder is screwed into the cap, whichmovement causes the distal pointed end 50 of the injection needle 46 topenetrate the membrane of the medicament container. It is however to benoticed that the threads 80, 78 between the needle cover and the cap,has a different direction of the pitch than the threads 70, 72 betweenthe needle holder and the cap.

When the needle assembly is delivered to the user the needle cover ispartially screwed onto the cap and the needle holder is also partiallyscrewed into the cap as shown in FIG. 6, with just a few threads inengagement with the cap. When the user then starts to turn the needlecover, this turning causes the needle holder to be screwed into the capwhereby the pointed distal end of the injection needle penetrates themembrane of the medicament holder and due to the different direction ofthe pitch the needle cover is screwed off the cap and may be removed.Preferably the pitches of the threads are chosen such that there is amajor longitudinal movement of the needle holder into the cap for asmall turning angle in order to prevent as much as possible turning or“drilling” of the distal end of the injection needle in the membrane. Atthe same time the pitch of the threads between the needle cover and thehub is preferably chosen such that the user only needs to turn theneedle cover about half a turn in order to perform the operation so asto avoid having to change grip in order to finish the operation.

In the previous embodiments, the cap 26 has previously been attached ina proper manner to the proximal end of the medicament container in asterile form.

In another embodiment, the injection needle assembly according to thepresent invention has the appearance of FIG. 1. Thus the distal pointedend of the injection needle is kept sterile by a protective cover 20,such as an aluminium foil or plastic foil or the like arranged on adistal opening 18 of the needle cover. The protective cover 20 ispreferably arranged with a grip means, such as a tab 22, forfacilitating the removal of the protective cover. When the injectionneedle assembly is to be attached to the medicament container/injectiondevice, the protective cover is torn away and the needle cap is attachedto the container and to the delivery.

It is to be understood that the embodiment described above and shown inthe drawings is to be regarded only as a non-limiting example of theinvention and that it may be modified in many ways within the scope ofthe patent claims.

The invention claimed is:
 1. An injection needle assembly havingopposite distal and proximal ends, comprising: (a) a tubular needlecover comprising, an open distal end having an inner diameter; an innercircumferential surface having, a plurality of axially extending ledges;and a first thread having a first pitch in a first direction; (b) atubular needle holder comprising, an injection needle; and an outercircumferential surface having two separate engagement devices, thefirst engagement device comprising cut-outs configured to engage theaxially extending ledges of the needle cover and the second engagementdevice comprising a second thread having a second pitch in a seconddirection; and (c) a tubular cap comprising, an outer circumferentialsurface having a third thread that engages the first thread of theneedle cover, a central passage having a diameter larger than the outercircumferential surface of the tubular needle holder and a fourth threadconfigured to engage the second thread of the needle holder, wherein thethird thread is configured to threadedly engage a proximal end of acontainer attachment device that operatively connects to a proximal endof a medicament container, wherein the inner diameter of the open distalend of the needle cover completely encloses the needle holder and thecap, where a protective cover seals the open distal end to maintainsterility of the needle.
 2. The needle assembly of claim 1, wherein thefirst direction of the first pitch is opposite of the second directionof the second pitch.
 3. The needle assembly of claim 1, wherein thefirst pitch of the first thread is the same as the second pitch of thesecond thread.
 4. The needle assembly of claim 1, further characterizedin that the first thread is partially engaged with the third thread andthe second thread is partially engaged with the fourth thread when theneedle holder and the cap are sealed within the needle cover by theprotective cover.
 5. The needle assembly of claim 1, wherein thecontainer attachment device is configured for attachment to a containerholder of a drug delivery device.